נק' מוניטין:
28,609
Recently, Morris [1] reported the results of an interesting literature review on the association between nutrition and Alzheimer disease (AD), focusing particularly on dietary fats. The author collected epidemiological data, mostly from Northern Europe, showing an inverse relationship between fish consumption and dementia. Morris attributed this effect to the omega-3 polyunsaturated fatty acids (n-3PUFA) which are involved in the neuronal membrane and in the maintenance of brain function [1]. However, the author stressed that, despite the well-demonstrated decreased AD risk in populations with elevated intakes of fish and n-3PUFA, baseline plasma n-3PUFA concentrations could not predict dementia in the Canadian Study of Health and Aging [1,2]. Furthermore, clinical trials failed to show any protective effect of n-3PUFA supplementation on cognitive decline in advanced-stage AD [1,2].
The main explanations for these mixed results could be that either the intake of n-3PUFA is efficient only in primary prevention at the mild cognitive impairment or mild AD dementia stages [2], or another constituent of fish could prevent dementia. For instance, fatty fish traditionally consumed in Northern Europe are rich not only in n-3PUFA, but also in vitamin D, which is a recently recognized neurosteroid hormone [3,4]. Vitamin D is essential for neurophysiological function, regulation of neurotransmitters or neurotrophic factors, and cerebral anti-oxydant, anti-inflammatory and anti-ischemic mechanisms [3,4]. Vitamin D insufficiency may instead cause neuropathological dysfunction such as cognitive impairment. Annweiler et al. [3] recently conducted a systematic literature review on the association of vitamin D status with cognitive status in adults. The five selected cross-sectional studies highlighted an association between low vitamin D concentrations and global cognitive impairment [3], which was subsequently confirmed in more than 750 older community-dwelling women with a twofold higher risk of cognitive impairment for vitamin D deficiency compared to normal status [4]. Vitamin D cognitive implications are also supported by interventional studies, as Dhesi et al. [5] showed in 139 ambulatory older adults that a one-time intramuscular injection of 600 000 UI vitamin D improved the four-choice reaction time compared to placebo after 6 months of follow-up (t = −2.52, P < 0.01).
In conclusion, fish consumption appears to prevent dementia. This could be explained by the impact of a health-promoting lifestyle or by the fish itself. In this perspective, the ingestion of omega-3 acids but also of vitamin D should be taken into account.
The main explanations for these mixed results could be that either the intake of n-3PUFA is efficient only in primary prevention at the mild cognitive impairment or mild AD dementia stages [2], or another constituent of fish could prevent dementia. For instance, fatty fish traditionally consumed in Northern Europe are rich not only in n-3PUFA, but also in vitamin D, which is a recently recognized neurosteroid hormone [3,4]. Vitamin D is essential for neurophysiological function, regulation of neurotransmitters or neurotrophic factors, and cerebral anti-oxydant, anti-inflammatory and anti-ischemic mechanisms [3,4]. Vitamin D insufficiency may instead cause neuropathological dysfunction such as cognitive impairment. Annweiler et al. [3] recently conducted a systematic literature review on the association of vitamin D status with cognitive status in adults. The five selected cross-sectional studies highlighted an association between low vitamin D concentrations and global cognitive impairment [3], which was subsequently confirmed in more than 750 older community-dwelling women with a twofold higher risk of cognitive impairment for vitamin D deficiency compared to normal status [4]. Vitamin D cognitive implications are also supported by interventional studies, as Dhesi et al. [5] showed in 139 ambulatory older adults that a one-time intramuscular injection of 600 000 UI vitamin D improved the four-choice reaction time compared to placebo after 6 months of follow-up (t = −2.52, P < 0.01).
In conclusion, fish consumption appears to prevent dementia. This could be explained by the impact of a health-promoting lifestyle or by the fish itself. In this perspective, the ingestion of omega-3 acids but also of vitamin D should be taken into account.
בשבילנו זה לא משנה מי משניהם. לקחת גם וגם.
